olalalala man oh man.
The new 3 series are all 6 cylinder in-line but 323 is a 2300cc, 325 is a 2500cc and a 330 is a 3300c engine. They differ in power performance and fuel consumption.

Difference between 323 and 325 is minimal. Go for the 325.
In the US 325 were sold in 2006 only and after that 328 replaced them in 2007 and up.
You could find 325 in Japan though as a 2006 model or 2007.

BMW is one of those rare companies that sell you a "customized" car.
I mean by "customized" that you can order whatever option imaginable you want including the Idrive or Comfort Access. Some BMW dealers in some countries decide to sell the car with a minimal package of options that include the leather seats and/or comfort access.

Youa re buying a used car so it all depends whether the previous owner order his BMW with Comfort Access and /or Idrive.

So check the car you want to buy if it includes these options before buying it.